Small Craft Advisory 263, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
234 PM AKDT MON MAR 28 2011

.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS A LOW PRESSURE
SYSTEM OVER THE FAR SOUTHERN GULF WITH AN ASSOCIATED WEATHER
FRONT JUST WEST OF THE QUEEN CHARLOTTES. STATIONS OVER THE
SOUTHERN THIRD ARE REPORTING PERIODS OF RAIN FROM THE APPROACHING
WEATHER FRONT. THE NORTHERN HALF IS SEEING ISOLATED TO SCATTERED
SHOWERS BUT THERE IS SOME SUNNY BREAKS. THESE BREAKS WILL NOT
LAST LONG WITH THE WEATHER FRONT DRIFTING NORTH. WINDS ACROSS THE
FORECAST AREA ARE ON THE LIGHT SIDE WITH THE STRONGEST WINDS OVER
THE SE GULF AND CROSS SOUND WITH WITH SMALL CRAFT WINDS.

 THE UPPER TROF ASSOCIATED WITH THE SURFACE LOW WILL WEAKEN AS IT
LIFTS NORTH DUE TO ANOTHER FAST MOVING SHORTWAVE TROF MOVING OUT
OF THE NORTH PACIFIC THAT WILL CUT THE FIRST ONE OFF FROM THE
COLD AIR. AS THE FIRST TROF WEAKENS AND LIFTS INTO THE NORTHERN
GULF BY LATE TONIGHT THE SAME WILL HAPPEN TO THE SURFACE LOW. THE
WEATHER FRONT ASSOCIATED WITH WEAKENING WEATHER SYSTEM WILL LIFT
OVER THE PANHANDLE THROUGH TONIGHT TUE MORNING. SO WITH THE
SCATTERED SHOWERS OVER THE NORTHERN HALF THIS EVENING STEADY RAIN
WILL DEVELOP THROUGH THE LATE TUE MORNING OVER THE NORTH CENTRAL
INNER CHANNELS AS STRONGER MID-LEVEL DYNAMICS MOVE OVER THE
AREAS. THE SOUTHERN HALF OF THE PANHANDLE WILL REMAIN TO SEE
STEADY RAIN THROUGH THE SHORT TERM PERIOD WITH PERSISTENT ONSHORE
SW FLOW. THE RAIN WILL INCREASE BY THE AFTERNOON OVER THE
SOUTHERN AREAS AS ANOTHER FRONT FROM A LOW DRIFTING OUT OF THE
NORTH PACIFIC MOVES INTO THE SOUTHERN GULF.

 WIND WISE...THE SMALL CRAFT WINDS OVER THE SE GULF WILL SLOWLY
DRIFT NORTH THROUGH TONIGHT WITH THE FRONT AND INCREASE TO GALES
BY TUE AFTERNOON IN THE FAR NORTHERN PORTIONS OF THE GULF. THE
WINDS WILL DECREASE SOME OVER THE SE GULF THROUGH TUE BUT THIS
WILL NOT LAST LOG AS THE WINDS WILL BE ON THE INCREASE WITH THE
APPROACHING WEATHER FRONT/LOW. THE WINDS OVER THE INNER CHANNELS
WILL SLOWLY INCREASE FROM THE NORTH TO BE 15 KT OF LESS BUT FROM
FREDRICK SOUND SOUTHWARD THE WINDS WILL INCREASE TO 20 KT WITH
SMALL CRAFTS NEAR CLARENCE STRAIT. AS THE FRONT WEAKENS THROUGH
TUE SO WILL THE WINDS OVER THE INNER CHANNELS AS THE PRESSURE
GRADIENT RELAXES AND BECOMES MORE E/W FROM N/S.

 THERE IS GOOD MODEL AGREEMENT THROUGH THE NEXT 24 HOURS AND USED
A BLEND OF THE 12Z GFS AND 00Z EC FOR THE FORECAST TODAY.

 &&

 .LONG TERM...EXTENDED FORECAST IS THE TALE OF TWO SYSTEMS. ONE
AT THE BEGINNING OF THE LONG TERM PERIOD THAT HAS RELATIVELY GOOD
AGREEMENT BETWEEN THE MODELS AND ONE ARRIVING AROUND SUN NIGHT
AND MONDAY THAT THE MODELS CAN NOT QUITE GET A HANDLE ON. SYSTEM
NUMBER ONE ARRIVES TUES NIGHT WITH A FRONT ADVANCING ON THE
PANHANDLE. THE PARENT LOW IS WELL TO THE WEST SO WIND WISE THE
FRONT DOES NOT PACK MUCH OF A PUNCH. AT MOST HAVE MIN SMALL CRAFT
WINDS IN FOR THE OUTSIDE WATERS TUES NIGHT. AS FAR AS PRECIP,
CURRENTLY IT LOOKS LIKE THE MAIN MOISTURE PLUME WILL HIT THE
COAST JUST SOUTH OF THE PANHANDLE. EVEN SO AMPLE MOISTURE WILL BE
AVAILABLE TO SPREAD RAIN OVER THE ENTIRE PANHANDLE AS THE FRONT
COMES ASHORE. MODELS ARE IN BETTER AGREEMENT WITH THIS SYSTEM BUT
THE NAM APPEARS TO STILL BE JUST A BIT TOO SLOW WITH THE
PROGRESSION OF THE FRONT. WENT WITH THE GFS AND EC FOR FORECAST
UPDATES.

 BEHIND THE FRONT, THE REMAINS OF THE PARENT LOW WILL SET UP SHOP
IN THE NORTHWEST GULF AND SIT THERE THROUGH LATE WEEK. CONTINUED
DEEP SW FLOW WILL CONTINUE TO BRING RAIN SHOWERS TO THE PANHANDLE
THROUGH FRIDAY. SATURDAY MAY BRING SOME DRY WEATHER AS SOME LOW
LEVEL RIDGING MOVES IN.

 MODEL AGREEMENT STARTS TO DEGRADE BY THE WEEKEND AS THEY TRY TO
FIGURE OUT WHAT THE NEXT SYSTEM ENTERING THE GULF WILL DO. BEST
THAT THEY CAN FIGURE OUT RIGHT NOW IS THAT THERE WILL BE A
RELATIVELY STRONG LOW SOUTH OF THE ALASKA PENINSULA SAT THAT WILL
DISSIPATE AS IT MOVES INTO THE EASTERN GULF BY MON NIGHT. THEY
ARE NOT VERY CONSISTENT ON MODELING TRACK OR STRENGTH YET. MODELS
HAVE SLOWED THIS SYSTEM UP A BIT FROM YESTERDAY AS WELL. NOT
BRINGING IN THE FRONT UNTIL SUN NIGHT. IN LIGHT OF THE
INCONSISTENCIES DECIDED TO STICK WITH HPC GUIDANCE WHICH HAS MORE
WEIGHT APPLIED TO THE ENSEMBLE PRODUCTS. FORECAST CONFIDENCE IS
GOOD THROUGH FRIDAY THEN DROPS TO POOR FOR THE WEEKEND AND EARLY
NEXT WEEK.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ052.
         SMALL CRAFT ADVISORY FOR PKZ022-035-036-041>043-051.

&&

ABJ/EAL